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Thursday, October 09, 2014

Long Haul Voice, Video and Data via MPLS Networks

By: John Shepler

Many companies need to transport voice, video and data over long distances, between cities, coast to coast or even internationally. Both the Internet and dedicated private lines are ways to effectively do this. But there is another option that you may not be aware of. That’s using MPLS networks for the majority of the distance involved. Why does this make sense? How do you choose among the options?

Internet Transport
The big advantage of the Internet is that it is already in place. You can get from just about anywhere on Earth to anywhere else with a simple broadband connection at each end. If your location and your destination are already Internet connected, there is no need to do anything special even if your two locations have never communicated before. Just send your packets from the source address to the destination address and they’ll get there.

This system works great for email, Web pages and non-time critical file transfers. It starts to fall down on real time interactive communications, such as VoIP telephone calls and video conferences. The quality of transmission can vary all over the place from minute to minute. Security is nonexistent for anything sensitive unless you add your own encryption. That’s called creating a VPN tunnel.

The reason that the Internet works great for certain applications and not others lies in its design. The Internet grew out of a government research project for creating a robust computer network that could withstand all sorts of natural and manmade disasters. The Internet automatically does its best to get your packets where they are intended regardless of network congestion or line cuts and equipment failures.

The Internet will almost always get your files transferred… eventually. If the packet loss is high, multiple retransmissions may be needed to get a perfect copy at the far end. If some or all of the network is congested, your files will get through when they get their turn. Most of the time this is no problem, but on occasion there will be delays.

For voice and video, congestion, jitter and packet loss are disasters. If the content is sent as a complete file, it can be treated like data and transmitted without error. But, if the content is streaming or two-way, resending lost packets doesn’t much help. By the time they get there, the stream has moved on.

One way streaming voice and video works much better is when you use a buffer to load in the packets as they arrive and then feed them out to the application at the desired rate. The worse the network conditions, the bigger the buffer you need to ensure your stream won’t stop or break up.

Two-way real time streams are much more sensitive. Buffering doesn’t help because it only adds time delay or latency. You say something and the party at the far end hears it a second or two later. If you’ve ever tried to communicate via a geosynchronous satellite you know how annoying this can be, and that is only a half second to a second of latency.

Dedicated Private LInes
The consumer world is tied to the Internet and its vagaries. Businesses with quality, timeliness and security concerns have long used dedicated private lines to handle their traffic. The beauty of a private line is that it only goes from point to point and doesn’t need to be routed. Since these lines are dedicated to your exclusive use, you don’t get contentions with other traffic on the network. As long as you have sufficient bandwidth and a high quality connection, the line will be transparent to your packets.

Another important characteristic of private lines is security. It’s pretty difficult for anyone but the most dedicated and skilled snoops to “tap” your line and read your traffic. There is no public access because it’s your private line. These lines are highly secure but can be made more impenetrable by using encryption between end points.

Private lines beat the Internet in all but a couple of areas. One is cost and the other is connectivity. Using the Internet is cheap because the cost of all that network infrastructure is spread of millions and millions of users. Consumer and low cost business connections are bargain priced because they are shared bandwidth that is offered on a “best effort” basis without any performance guarantees.

Private lines are at the other end of the cost spectrum. The cost of the line and necessary support equipment is spread over one user… you. You have to pay the full cost of the line but you do have exclusive use and the security and high performance that comes with it. This can get pricy when you need a line that goes for thousands for many thousands of miles.

The other issue is that not all locations can be connected with many private lines. It’s true that T1 lines (1.5 Mbps) are pretty much universal, although they need to be specifically installed at each end before you can send any traffic. Higher bandwidth solutions, such as Ethernet over Copper, SONET fiber, and Ethernet over Fiber may not be available where you want to go.

Why MPLS Networks Make Sense
It seems like the perfect solution is a network that is widely available, like the Internet, but performs like private lines without the high costs. Perhaps surprisingly, there are such networks. They are called MPLS or Multi-Protocol Label Switching.

That mouthful of a name means a couple of important things. First of all, MPLS can transport a variety of protocols, including voice, video and data in most any format you need. Second, the label switching technology is unlike that of Internet routers, so MPLS networks are much harder to “hack.” Since there is no public access, the chances of some rogue troublemaker gaining access to the network are slim. For this reason, they are often called MPLS VPN networks because the technology of the network makes it virtually private without encryption. Of course, you can always add your own encryption to make your traffic even more impenetrable.

Yes, when you are using an MPLS network you are using a shared resource with many other customers of the network. However, it isn’t the free-for-all of the Internet. There’s no such thing as network neutrality on MPLS. Each customer pays for the bandwidth it needs (commonly called the CIR or committed information rate) and is guaranteed similar to private line performance with a service level agreement (SLA).

How about cost? Since the cost of the MPLS network infrastructure and operating expenses are spread over many clients, your cost of using the network is considerably less than leasing your own private lines. This is especially true if you are connecting internationally or need multiple private lines between different destinations. Think of the MPLS network as a cloud that is connected to each of your locations by a much shorter private line. The network cloud takes care of routing the traffic among your last mile connections.

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